Hernandez (12-5) limited the Tribe to one run on seven hits and struck out five over 7 2/3 innings in his first performance since notching a perfect game.
Hernandez boasts a 1.53 ERA over his last dozen starts and Tuesday led the Mariners to their 14th win in their last 15 home games.
Eric Thames added a solo homer and John Jaso drove in a run with a single for the Mariners.
Ramon Hernandez (0-2) took the loss, giving up four runs, three hits and two walks over six-plus innings.
Cleveland tied the score at 1-1 on Casey Kotchman's RBI single in the seventh, but Seattle bounced back with four runs in their half of the inning to take control and send the Indians to their seventh consecutive loss.